This invention relates to photographic apparatus of the type having a rotatable sleeve encompassing an objective lens. The lens is movable along a longitudinal axis for automatically focusing any object within a predetermined focusing range. More particularly this invention can be used in conjunction with an "Automatic Focusing System" disclosed by Hendrickson and Johnston in a patent application filed Ser. No. 536,666 filed on Dec. 26, 1974 herewith and assigned to the same assignee.
Photograhic apparatus of the type described include means for emitting a beam of light toward the object to be photographed, and photoreceptor means adapted to receive a portion of the light beam reflected from the object. The photoreceptor means produce a pair of electrical signals, corresponding to the amount of light received. As explained in detail in the above-described disclosure of Hendrickson and Johnston, the electrical signals are passed through circuitry for energizing mechanical means, including an electric motor. The electric motor turns the rotatable sleeve, thereby automatically moving the objective lens along the longitudinal axis toward a position for properly focusing the object.
The present invention most particularly relates to a mechanism which permits the photorecptor means to be pivoted relative to the photographic apparatus upon automatic adjustment of th rotatable sleeve. This pivoting action of the photoreceptor means tends to equalize the strength of the electrical signals produced thereby. When the electrical signals are so equalized, electric circuitry de-energizes the electric motor, thereby maintaining the objective lens in proper position for focusing the object to be photographed.